Lift wash-through facility

ABSTRACT

An apparatus for pumping fluid, the apparatus including a pump housing including a plunger connected to a terminal end of a coiled tubing and a first port. The apparatus further including the plunger configured to move longitudinally upward and downward, wherein the plunger includes a second port and a surface pumping unit configured to modulate between two modes, a first mode configured to limit a stroke length of the plunger so that the first and second ports do not engage, and a second mode wherein the first and second ports engage. Also, a method for pumping fluid into a wellbore using an apparatus, the method comprising inserting a housing including a coiled tubing and a plunger into the wellbore, wherein the plunger is located at a terminal end of the coiled tubing, and wherein the housing includes a first port and a plunger includes a second port. The method further including moving the plunger longitudinally upward and downward within the housing wherein a stroke length of the plunger is limited during the moving the plunger and extracting fluid from the wellbore. The method further including extracting fluid from the wellbore, pulling the plunger longitudinally upward until the first and second ports are aligned, and circulating fluid into the wellbore through the coiled rubbing and first and second ports discharging into an annulus of the wellbore.

BACKGROUND

1. Field of Disclosure

In general, embodiments of the present disclosure generally provide methods and apparatuses for pumping fluid from a wellbore. More specifically, embodiments disclosed herein relate to a single apparatus that facilitates both producing hyrocarbons and circulating fluid downhole.

2. Background Art

Typically, wells employ a pump system configuration for extracting oil and gas from the earth. A conventional oil well pumping system incorporates a down hole pump, a sucker rod string extending from the down hole pump to the surface and a pump jack or pumping unit at the surface attached to the upper end of the sucker rod string for reciprocating the sucker rods and activating the down hole pump. An example of such conventional pump system is shown in FIG. 1A. In pump system (1), a wellbore casing (11) extends downward from the surface to various production formations (5). Casing (11) is a tubular that lines the inside of the wellbore and includes perforations (10) in the region of the various production formations (5) that allow fluids from the formations to enter the wellbore. The casing may be a steel casing. A tubing string (2) is located within the casing (11). The tubing string may be a coiled tubing, a threaded tubing, or any other suitable type of tubing. The tubing string (2) extends downward from a well-head (12) to the formations. A plunger (4) is located at the terminal end of the tubing string. The plunger resides in a pump chamber (6) and is operatively connected to a solid sucker rod string (3). The sucker rod string (3) is operatively connected to beam pumping unit (8) at the surface. The beam pumping unit (8) is configured to raise and lower the sucker rod (3) to move the plunger (104) in relation to the pump chamber (6). The plunger motion, together with the operation of the check valves (7), causes the transfer of fluids from below the plunger (4) to the annulus between the sucker rod (3) and the tubing string (2). Repeated raising and lowering of the plunger (4) transfers sufficient fluid to fill the tubing string (2) and forces fluid to flow from the well to the surface.

FIG. 1B shows an enlarged cross-section view of the subsurface pump chamber (6), plunger (4) and check valves (7). The check valves (7) are used to prevent backflow of fluid.

During the process of extracting oil and gas using a pumping system as described above, it is often desirable to remove all solid materials in the well bore as well as removal of cement, debris, metal and other materials which may cling to the wall of the tubular or may be laying on the side or bottom of a partially horizontal tubular. Currently this process is accomplished by running a tubular (commonly called a “work string”) in to or near the bottom of the well. Fluid is then circulated through or down the work string and into the annulus between the tubular and wellbore. More specifically, water or other fluids are pumped down the wellbore through the work string and out the bottom of the string. The fluid flows through the annulus between the work string and the wellbore and out the surface, carrying away any matter loosened during workover or production phases of the well.

Circulation is accomplished by pumping fluid down the work string and back to the surface through the annulus between the work string and casing. Often times, the pumping system used to extract oil and gas from the wellbore is replaced by a separate system configured to perform wellbore circulation. Thus, the pumping system used for extraction of oil and gas may be removed from the wellbore entirely to allow for the work string to be inserted downhole to treat the wellbore. Applications requiring different tools for production and circulating of fluids in the wellbore can increase the cost of production due to the cost of the tools, the cost of changing the tools, and costs associated with production downtime.

Therefore, there exists a need for a more efficient production system.

SUMMARY

In one aspect, embodiments disclosed herein include an apparatus for pumping fluid, the apparatus including a pump housing including a plunger connected to a terminal end of a coiled tubing and a first port. The apparatus further including the plunger configured to move longitudinally upward and downward, wherein the plunger includes a second port and a surface pumping unit configured to modulate between two modes, a first mode configured to limit a stroke length of the plunger so that the first and second ports do not engage, and a second mode wherein the first and second ports engage.

In another aspect, embodiments disclosed herein include a method for pumping fluid into a wellbore using an apparatus, the method comprising inserting a housing including a coiled tubing and a plunger into the wellbore, wherein the plunger is located at a terminal end of the coiled tubing, and wherein the housing includes a first port and a plunger includes a second port. The method further including moving the plunger longitudinally upward and downward within the housing wherein a stroke length of the plunger is limited during the moving the plunger and extracting fluid from the wellbore. The method further including extracting fluid from th wellbore, pulling the plunger longitudinally upward until the first and second ports are aligned, and circulating fluid into the wellbore through the coiled rubbing and first and second ports discharging into an annulus of the wellbore.

Other aspects of the invention will be apparent from the following description and the appended claims.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A-1B show a conventional pumping system.

FIGS. 2A-2E show a lift wash-through facility in accordance with one or more embodiments of the disclosure.

FIGS. 3A-3B show an example of a housing profile in accordance with one or more embodiments of the disclosure.

FIG. 4 shows a flow chart in accordance with one or more embodiments of the disclosure.

DETAILED DESCRIPTION

Specific embodiments of the disclosure will now be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency.

In the following detailed description of embodiments of the disclosure, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.

In general, embodiments of the disclosure provide a method and apparatus for pumping fluid from a wellbore. More specifically, embodiments disclosed herein relate to a single apparatus that facilitates both producing hyrocarbons and circulating fluid downhole.

FIGS. 2A-2E show an apparatus for pumping fluid in accordance with embodiments of the disclosure. Specifically, FIGS. 2A-2E show an apparatus (100) for pumping fluid in a wellbore that includes a coiled tubing (102), a housing (104), and a plunger (106). Both the housing (104) and the plunger (106) include ports (108, 110). Each of the aforementioned components of the apparatus are described below.

FIG. 2A shows the apparatus (100) in run in hole (RIH) pinned mode. That is, the apparatus (100) is shown in a normal “at rest” position in FIG. 2A. The coiled tubing (102) is typically coiled on a large spool at the surface. Those skilled in the art will appreciate that the invention is not limited to the use of coiled tubing, and any other suitable type of tubing string, such as threaded tubing, may be used. The plunger (106) is located at the terminal end of the coiled tubing (102) (i.e., the end that is inserted into the wellbore). The plunger (106) may be made of ceramic, steel, composite, or any other suitable material. The housing (104) is configured to house both the coiled tubing (102) and the plunger (106). The housing (104) may be made of steel or any other suitable material.

In one or more embodiments disclosed herein, a first port (108) exists on the plunger (106), and a second port (110) exists on the housing (104). The first port (108) may be any object, such as a protrusion, a recess, an indentation, a hole, etc. configured to mate (i.e., engage) with the second port (110). In one or more embodiments of the disclosure, the first and second port do not engage or align during normal pumping activity, i.e., when oil and/or gas is extracted from the wellbore. However, the first and second ports (108, 110) are configured to align when the apparatus (100) is in circulation mode (described in detail below).

In one or more embodiments disclosed herein, a surface pumping unit (not shown) is operatively connected to the coiled tubing (102). The surface pumping unit includes a bridle and bridle cables that are configured to attach and grab a specific location along the length of the coiled tubing (102). In one or more embodiments disclosed herein, the surface pumping unit is configured to limit the amplitude of the pump stroke that is performed by the plunger (106). The surface pumping unit is configured to limit the stroke of the plunger to a down stroke limit and to an up stroke limit. Limiting the stroke prevents the first and second ports from coinciding (i.e., engaging), when the apparatus (100) is not in circulation mode.

In FIG. 2B, the apparatus (100) is shown in a downward movement, where the plunger (106) of the apparatus (100) moves downhole, as indicated by the downward arrow alongside the apparatus. More specifically, the position of the plunger in FIG. 2B is shown at the down stroke limit (i.e., the greatest longitudinal position that the plunger can move downward, as limited by the settings on the surface pumping unit, which moves the coiled tubing downhole). As can be seen in FIG. 2B, the ports (108, 110) of the housing (104) and the plunger (106) are displaced in the greatest longitudinally distant position as is permitted by the stroke limiter of the surface pump. In certain embodiments, the greatest longitudinal distance may be, for example, about 30 feet.

FIG. 2C shows the apparatus (100) in the mid-stroke position, moving upward, as indicated by the upward arrow shown alongside the apparatus (100).

FIG. 2D shows the apparatus (100) in the up stroke position, where the plunger (106) has moved as far upward as is permitted by the stroke limiter of the surface pumping unit, as indicated by the upward arrow alongside the apparatus. More specifically, the position of the plunger (106) in FIG. 2D is shown at a longitudinally proximal position, such that ports (108, 110) are adjacent but not engaging, as is limited by the settings on the surface pumping unit, which moves the coiled tubing (102) uphole. As may be seen in FIG. 2D, the profiles of the housing (104) and the plunger (106) are as close together as is permitted by the stroke limiter of the surface pumping unit, without actually engaging with one another.

FIG. 2E shows the circulation mode of the apparatus, in accordance with one or more embodiments disclosed herein. In one or more embodiments disclosed herein, the circulation mode circulates fluid downhole through coiled tubing (102) into the wellbore and then back up the wellbore through the annulus. As such, if the annulus is closed, the fluid will be forced into the reservoir. In one or more embodiments of the disclosure, the circulation mode is used to circulate treatment fluids for treating the wellbore. For example in one or more embodiments of the disclosure, fluids that may be circulated for wellbore treatment may include, but are not limited to, acids, polymers, corrosion inhibitors, surfactants, stimulation fluids, heated fluids for dissolving wax or removing scale, and/or any combination thereof.

In FIG. 2E, when the apparatus is placed in circulation mode, the first port (108) located on the outer surface of the plunger (106) and the second port (110) located on the inner surface of the housing (104) align and engage. That is, the plunger is moved upward past the upward stroke limit, to the top-most position within the housing. Thus, as shown in FIG. 2E, the top surface of the plunger (106) is adjacent to the bottom surface of the housing (104). In one or more embodiments disclosed herein, the plunger (106) is brought to the top-most position by adjusting the grip of the surface pumping unit along the length of the coiled tubing (102). Said another way, the location along the length of the coiled tubing (102) where the surface pump grabs the coiled tubing (102) is shifted such that the upward stroke of the plunger (106) moves past the limit imposed by the surface pumping unit. In one embodiment, the location along the length of the coiled tubing (102) may be adjusted by engaging the surface pumping unit with the coiled tubing (102) such that less coiled tubing (102) goes downhole during a down stroke. Because the length of coiled tubing (102) available to be disposed downhole has decreased, the upward stroke of the surface pump moves plunger (106) farther upward within housing (104), thereby allowing first and second ports (108, 110) to engage. Upon engagement, first and second ports (108, 110) may provide a flow path for fluid between plunger (106), housing (104) and the annulus of the wellbore.

FIGS. 3A-3B show examples of the housing and the plunger in accordance with one or more embodiments of the disclosure. Specifically, FIG. 3A shows an example profile (300) for aligning the port located on the inside of the housing when working in conjunction with FIG. 3B, a corresponding profile (302) associated with the port located on the outside of the plunger. As described above, the profiles may be any object capable of being operatively aligned or engaged. The profile is a detailed illustration of the shape and/or properties of the mechanism that configure the ports to engage in circulation mode. In one or more embodiments of the disclosure, the first profile matches the second profile such that the first and second profiles are configured to engage together to align the first and second ports when the plunger is pulled to the top-most position within the housing.

In FIG. 3A, the profile (300) is shown as a V-shaped groove on the inside surface of the housing. In FIG. 3B, the profile (302) is shown as a matching V-shaped groove on the outer surface of the plunger. When the plunger is pulled up to the top-most position of the housing, the V-shaped groove on the inner surface of the housing is inserted into the matching V-shaped groove on the outer surface of the plunger. Thus, when the ports align, the two grooves engage, which causes the plunger to remain stationary when treatment fluids are circulated into the wellbore. The profile (302) on the plunger may twist into the profile on the housing or may directly insert into the profile on the housing.

Those skilled in the art will appreciate that the example profiles shown in FIGS. 3A-3B are not meant to limit the invention, and the profiles may take any suitable shape or form. For example, the first port profile may be a peg, and the second port profile may be a groove into which the peg is inserted. Alternatively, the first and second profiles may be splines. In another embodiment, the first port profile may start out wide at the bottom end and become narrow at the top end such that the second port profile twists into the narrowing first port profile when the plunger is pulled to the top-most position within the housing. Additionally, those of ordinary skill in the art will appreciate that the corresponding and engagable profiles may include other geometries that allow fluid communication between the first and second ports. In addition to profiles (300, 302) being corresponding and engagable, the inner flow paths of the ports may also include various geometries. For example, in certain applications, inner flow paths may be circular (as illustrated in FIGS. 3A and 3B), oblong, elliptical, etc.

In certain embodiments, profiles (300, 302) are configured to engage and mate with one another upon rotation of the plunger relative to the housing. Because the housing is stationary within the wellbore, the coiled tubing may be rotated from the surface, thereby rotating the plunger as the plunger is pulled longitudinally upward toward the surface. As the plunger is pulled longitudinally upward, profiles (300, 302) slidably engage one another. The sliding engagement may occur, for example, as profile 300 of the plunger rotates relative to profile 302 of the housing. Because the plunger may rotate within the housing, profile 300 of the plunger may also rotate relative to profile 302 of the housing during engagement. While profiles (300, 302) are engaged, fluid may flow from the surface, through the coiled tubing, out of the ports, and into the annulus of the borehole. In alternate embodiments, a swivel may be used in the plunger or the coiled tubing to facilitate alignment of profiles (300, 302) as the profiles (300, 302) engage one another. Those of ordinary skill in the art will appreciate that various types of swivels may be used, such as, for example, a cylindrical rod disposed within a support structure and configured to rotate horizontally therein.

FIG. 4 illustrates a method for using an apparatus in accordance with one or more embodiments disclosed herein. Initially, the housing is inserted into the wellbore (ST 400). Next, the coiled tubing, which includes the plunger affixed to a terminal end, is inserted into the housing (ST 402). Alternatively, the coiled tubing and the plunger may be inserted into the housing at the surface, and subsequently, the housing including the plunger may be inserted into the wellbore. At this stage, the surface pumping unit that is configured to move the coiled tubing and plunger upward and downward is pre-configured to limit the pumping stroke of the plunger (ST 404). That is, the amplitude (or stroke length) of the plunger is limited by configuring settings on the surface pumping unit such that the surface pumping unit does not move the plunger past an up stroke limit and below a down stroke limit.

The surface pumping unit then moves the plunger in a pump motion, longitudinally upward to the up stroke limit and then longitudinally downward to the down stroke limit (ST 406). The up stroke limit and the down stroke limit may vary according to design constraints of a particular operations. For example, in certain operations, the stroke limits may be determined based on the length or internal diameter of the plunder or housing. In other operations, the stroke limits may be determined based on the type of fluid being produced, the volume of fluid being produced, the pressure of the system, etc.

When required, the pump apparatus may be placed in circulation mode. Circulation mode may be required as part of conventional maintenance operations to maintain the integrity of and clean debris from the wellbore. To facilitate circulation mode, the grip of the surface pumping unit along the length of the coil tubing is adjusted such that the bridle of the surface pump grabs the coiled tubing at a location below the original location (ST 408). By adjusting the grip of the surface pumping unit, the plunger may be pulled upward past the up stroke limit, thereby pulling the plunger to the top-most position within the housing (ST 410). When the plunger is pulled to the top-most position within the housing, the ports on the housing and the plunger engage and align (ST 412). The engagement of the ports facilitates the circulation of fluids to treat the wellbore during circulation mode.

In certain embodiments, when the pump apparatus is placed in circulation mode, the coiled tubing or plunger may be rotated, thereby causing the ports of the housing and plunger to align. In certain embodiments, the pump apparatus may include a swivel, thereby allowing the profiles to engage and align the ports. In other embodiments, the profiles of the ports engage and mate upon contact, as the plunger is pulled longitudinally upward. As such, the pump apparatus may include ports with self-aligning profiles, thereby providing a flow path between the pump apparatus and the annulus of the wellbore.

More specifically, during circulation, fluid is circulated downstream into the wellbore and back up through the annulus. In one or more embodiments of the disclosure, the plunger is stationary when the apparatus is placed in circulation mode. Alternatively, the plunger may be reciprocated to provide intermittent circulation or jetting.

In certain embodiments, fluids may be forced into the well and/or reservoir against pressure in a process referred to in the art as “bullheading.” Bullheading may be used to chemically and/or physically treat the well and/or reservoir to, for example, improve production, prevent corrosion, prevent scale deposition etc. . . .

Advantageously, embodiments of the disclosure provide a single apparatus that facilitates both extraction of wellbore production fluids and the circulation of fluids to treat the wellbore. The apparatus of the present disclosure eliminates the need for a separate circulation apparatus, and provides an efficient, quick, and low cost apparatus and method for combining the aforementioned processes during workover and production.

Advantageously, embodiments of the present disclosure may provide self-aligning port profiles that allow movement of a plunger of the pump apparatus to provide a flow path from the surface to the annulus of the wellbore. Because the port profiles are self-aligning, the pump apparatus may efficiently modulate between production and circulating modes. By allowing faster maintenance and cleaning operations, the wellbore may be cleaned and maintenance may be performed without lengthy and expensive operations that may involve removing the pump apparatus or a portion of the pump apparatus from the wellbore.

While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims. 

1. An apparatus for pumping fluid, comprising: a pump housing comprising: a plunger connected to a terminal end of a coiled tubing, and a first port; the plunger configured to move longitudinally upward and downward, wherein the plunger comprises a second port; and a surface pumping unit configured to modulate between two modes, a first mode configured to limit a stroke length of the plunger so that the first and second ports do not engage, and a second mode wherein the first and second ports engage.
 2. The apparatus of claim 1, wherein the first port comprises a first profile on the inner surface of the housing.
 3. The apparatus of claim 2, wherein the second port comprise a second profile on the outer surface of the plunger.
 4. The apparatus of claim 3, wherein the first and second profiles are configured to align when the apparatus is in the second mode.
 5. The apparatus of claim 1, wherein the stroke length of the plunger is adjusted by modifying parameters of the surface pumping unit.
 6. The apparatus of claim 5, wherein parameter comprises a grip location.
 7. The apparatus of claim 6, wherein the grip location decreases a length of the coiled tubing that is disposed in a wellbore.
 8. The apparatus of claim 7, wherein well treatment fluids comprise one selected from a group consisting of acids, chemicals, corrosion inhibitors, surfactants, and heated fluid treatments.
 9. The apparatus of claim 1, wherein the plunger is stationary in circulation mode.
 10. The apparatus of claim 1, further comprising a swivel configured to allow alignment of the first and second ports.
 11. A method for pumping fluid into a wellbore using an apparatus, comprising: inserting a housing comprising a coiled tubing and a plunger into the wellbore, wherein the plunger is located at a terminal end of the coiled tubing, wherein the housing comprises a first port and the plunger comprises a second port; moving the plunger longitudinally upward and downward within the housing, wherein a stroke length of the plunger is limited during the moving the plunger; extracting fluid from the wellbore; pulling the plunger longitudinally upward until the first and second ports are aligned; and circulating fluid into the wellbore through the coiled tubing and first and second ports discharging into an annulus of the wellbore.
 12. The method of claim 11, wherein fluid comprises well treatment fluid.
 13. The method of claim 12, wherein well treatment fluids comprise one selected from a group consisting of acids, polymers, corrosion inhibitors, surfactants, and heated fluid treatments.
 14. The method of claim 11, wherein the plunger is stationary in circulation mode.
 15. The method of claim 11, wherein the stroke length of the plunger is adjusted by modifying parameters of a surface pumping unit.
 16. The method of claim 11, further comprising adjusting a grip of the surface pumping unit to change a location along a length of the coiled tubing where the surface pumping unit holds the coiled tubing.
 17. The method of claim 11, wherein the housing comprises a swivel.
 18. The method of claim 17, further comprising rotating a swivel to align the first port and second port.
 19. The method of claim 11, further comprising closing an annulus of the wellbore, and pumping fluid into formation. 